Unanswered Questions
179 questions with no upvoted or accepted answers
11
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Is it possible to calculate non-resonant Raman coefficient in Quantum ESPRESSO for systems that require smearing to converge?
In Quantum ESPRESSO turning lraman to true in the ph.x input is not possible if the material is made to converge using smearing. Is there any way to circumvent this, as my material isn't a metallic a ...
11
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145
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Have FDTD methods made inroads into dynamical simulation of electron and/or X-ray scattering by crystals?
I'm afraid this question might be too basic or too naive or both, but here goes!
For optical diffraction by periodic nano-structures (gratings, semiconductor manufacturing metrology) the rigorous ...
9
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184
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How to do parity analysis of band extrema?
To check whether electronic transitions are allowed between valence band maximum (VBM) and conduction band minimum (CBM) as per Laporte's rule, the parity of VBM/CBM is needed to be known. This paper ...
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8
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How do I identify an oblique surface mesh?
I have drawn three surface meshes from a hexagonal material for the $(0001)$, $(1\bar{1}00)$ and $(1\bar{1}01)$.
The first one would be the top horizontal surface of the hexagonal structure, the ...
- 15.9k
7
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46
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How to determine if hybridization takes place between orbitals in an ab initio calculation using Quantum ESPRESSO?
I'm using Quantum ESPRESSO to determine the electronic properties of systems. Now I want to confirm if hybridization takes place between orbitals. I have generated density of states and projected ...
7
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157
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Correct method for structure optimization using DFT tools
Lets's say I want to start off DFT calculations for a material whose experimental cell constants are known. So I have two ways to get the correct structure to later on calculate, say, band structure ...
- 939
7
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57
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Database (or table) of functions obeying symmetry properties of space groups
I'm looking for a table or database containing mathematical functions that belong to crystallographic space groups by having the same symmetry elements.
Imagine a 2D square planar lattice. It has a 4-...
7
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448
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Straightforward formalism to get sets of lattice vectors of fcc (111), (110) and (100) facet surfaces that I can also cite?
I am simulating low energy electron diffraction (LEED) from a polyfaceted sample. Usually it's a single, well-defined flat crystalline surface.
Since low energy electrons (below a few hundred eV) only ...
- 2,074
7
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201
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How to convert lab frame quaternions and plane normal to misorientation quaternion and crystal plane normal for grain boundaries?
Background
Let qA and qB represent unit, orientation quaternions of grain A and grain B of a grain boundary in the lab reference ...
- 15.9k
6
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125
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Why are some pseudopotentials not readable in Quantum Espresso?
I am using the pseudopotentials generated using "atomic" code by A. Dal Corso after downloading the pslibrary.0.3.1. ...
- 20.1k
6
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229
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Regarding use of GCMC to add water molecules
I am working on a goethite system, and wish to fill the unit cell with water molecules for AIMD simulation using quantum espresso. For this, some papers[1],[2] indicated the use of Grand Canonical ...
5
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Conceptual question about trap levels in semiconductors and their occupancy
[Cross posted from physics stack exchange as recommended in the comments, although I couldn't find the policies for that.]
Some fairly basic conceptual questions arose as I was doing some DFT and ...
- 1,154
5
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46
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Unexplained spins in undoped alumina
I have been trying to construct the spin-density plot of an α-alumina supercell. Being a diamagnetic material, I would not expect to see any spins in this structure.
However, when running a spin-...
- 1,003
5
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42
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Reference of Fermi energy in Quantum Espresso
I want to know what is the reference of Fermi energy calculated in scf run of Quantum Espresso.
- 453
5
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63
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Number of phonons into a supercell
I am a masters student who's struggling with Quantum ESPRESSO for my thesis. I'm at the end of my internship and I think I may have done some conceptual error, which of course are linked to practical ...